Organosol of fluoride colloid particle and method for producing the same

Abstract

There is provided an organosol of surface-modified fluoride colloid particles obtained by coating the surface of a fluoride colloid particle as a core with an organophosphorus compound and a method for producing the organosol. An organosol of a surface-modified fluoride colloid particle comprising: a fluoride colloid particle as a core; and at least one type of an organophosphorus compound selected from a group consisting of organophosphorus compounds represented by the following general formula (1), (2), and (3): (R—O) n P(═O)(OM) 3-n   (1) (R—O) n P(OM) 3-n   (2) (R) n P(═O)(OM) 3-n   (3) where R represents a substituted or unsubstituted alkyl group, alkenyl group or aryl group, M represents a hydrogen atom, an alkali metal or NZ 4 (Z represents a hydrogen atom or an alkyl group); and n represents an integer of 1 or 2, the organophosphorus compound coating a surface of the fluoride colloid particle.

1. An organosol of a surface-modified fluoride colloid particle comprising:
 an organic solvent; 
 a fluoride colloid particle having a primary particle diameter of 3 to 100 nm according to an observation through an electronic microscope as a core; and 
 at least one type of an organophosphorus compound selected from a group consisting of phenylphosphonic acid, an alkali metal salt of the phenylphosphonic acid, and an ammonium salt of the phenylphosphonic acid, the organophosphorus compound coating a surface of the fluoride colloid particle. 
 
     
     
       2. The organosol of a fluoride colloid particle according to  claim 1 , wherein a coating amount of the organophosphorus compound is 0.1 to 50% by mass based on a mass of the fluoride colloid particle. 
     
     
       3. The organosol of a fluoride colloid particle according to  claim 1 , wherein the fluoride colloid particle is magnesium fluoride, sodium magnesium fluoride, or a hydrate salt of the magnesium fluoride or the sodium magnesium fluoride. 
     
     
       4. The organosol of a fluoride colloid particle according to  claim 1 , wherein the organic solvent is a hydrophobic organic solvent. 
     
     
       5. A method for producing the organosol of a fluoride colloid particle as claimed in  claim 1 , the method comprising:
 mixing a sol of a fluoride colloid particle with an organophosphorus compound. 
 
     
     
       6. The method for producing an organosol of a fluoride colloid particle according to  claim 5 , the method further comprising the following steps of (a), (b), and (c):
 (a) producing a water-based sol of a fluoride colloid; 
 (b) substituting an aqueous solvent of the water-based sol of a fluoride colloid with a hydrophilic organic solvent; and 
 (c) substituting a solvent of a hydrophilic organic solvent sol of a fluoride colloid with a hydrophobic organic solvent; wherein during at least one step, at least one type of an organophosphorus compound selected from a group consisting of phenylphosphonic acid, an alkali metal salt of the phenylphosphonic acid, and an ammonium salt of the phenylphosphonic acid, is added.